瞬态机械阻抗法在工程基桩缺陷诊断中的应用研究
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摘要
以1根完整无缺陷基桩和3根预先设置缺陷的基桩为研究对象,采用奥地利德威DEWESoft振动测试系统,基于瞬态机械阻抗法,对比完整基桩,对3根有缺陷基桩进行了诊断分析,探讨了基桩固有频率测试的可行性及刚度测量的可重复性。结果表明:基于固有频率的机械阻抗法多次重复测试结果一致性较好,测试结果可以反映缺陷位置、缺陷处的有效桩径,基桩缺陷程度与其刚度值具有一定的正相关关系。因此,推荐采用同一工地、地质情况基本相同的基桩刚度测试统计值,运用数理统计等方法确定一个合理的刚度值界限作为基桩缺陷程度的划分依据,以达到定量评估基桩质量的目的。
In this paper,one non-fault pile and three pre-placed piles with faults are taken as the object of study. The test is carried out using the Austrian DEWESoft vibration test system. In contrast to the intact foundation pile, three defective piles based on the transient mechanical impedance method are diagnosed and analyzed. The feasibility of testing the natural frequencies of piles and the repeatability of stiffness measurements are discussed. The results show that the mechanical impedance method based on natural frequency has good consistency in repeated test results. The test results can reflect the defect location and the effective diameter of the defect. The defect degree of the foundation pile has a positive correlation with its stiffness value. It is recommended to use the same statistic value of pile stiffness test in the same site and geological conditions,and to determine a reasonable limit of stiffness value by mathematical statistics as the basis for the classification of defect degree of pile,so as to achieve the purpose of quantitative evaluation of pile quality.
In this paper,one non-fault pile and three pre-placed piles with faults are taken as the object of study. The test is carried out using the Austrian DEWESoft vibration test system. In contrast to the intact foundation pile, three defective piles based on the transient mechanical impedance method are diagnosed and analyzed. The feasibility of testing the natural frequencies of piles and the repeatability of stiffness measurements are discussed. The results show that the mechanical impedance method based on natural frequency has good consistency in repeated test results. The test results can reflect the defect location and the effective diameter of the defect. The defect degree of the foundation pile has a positive correlation with its stiffness value. It is recommended to use the same statistic value of pile stiffness test in the same site and geological conditions,and to determine a reasonable limit of stiffness value by mathematical statistics as the basis for the classification of defect degree of pile,so as to achieve the purpose of quantitative evaluation of pile quality.
引文
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[8]哈图,冀慧星,刘博.基于动测法的基桩刚度验证试验研究[J].科学技术与工程,2016,16(13):101-105.
[9]张智.机械阻抗法测定基桩刚度的研究[D].呼和浩特:内蒙古工业大学,2014.
[2]董承全,张佰战,胡在良,等.桩身完整性不同检测方法的对比试验[J].铁道建筑,2009,(12):75-77.
[3]韩婷.青岛地区桩基础检测技术研究与实测分析[D].青岛:青岛理工大学,2015.
[4]李林杰.基于动刚度测试的既有桥梁桩基础状态评价研究[D].北京:中国铁道科学研究院,2013.
[5]刘建磊,马蒙,李林杰,等.基于实测动刚度的桥桩承载能力评估研究[J].岩土力学,2015,(s2):571-576.
[6]李权福,王振卿,刘建磊.动刚度法在既有桥梁桩基础状态评估中的应用研究[J].铁道建筑,2014,(05):27-30.
[7]冀慧星.机械阻抗法在桩基故障诊断与刚度测试中的应用研究[D].呼和浩特,内蒙古工业大学, 2016.
[8]哈图,冀慧星,刘博.基于动测法的基桩刚度验证试验研究[J].科学技术与工程,2016,16(13):101-105.
[9]张智.机械阻抗法测定基桩刚度的研究[D].呼和浩特:内蒙古工业大学,2014.